The present invention relates to a tennis-ball delivery system, said system having a rebound wall that is substantially vertical, and a ball-collection trough that is disposed at the base of said rebound wall; a ramp, having an ascending and a descending portion connecting the rebound wall to the playing area, the rebound wall or ramp, respectively, having a frame with a flexible covering consisting of pipe sections that are inserted into each other. Systems of this type are used to collect balls that a player has hit against the vertical rebound wall or the ramp, and then moves these balls to a delivery system that, in its turn, passes them to a container. A ball thrower is usually connected to this container. Within the collection trough, the balls may be moved by gravity alone as disclosed in DE-OS No. 23 34 849, or they may be moved by a conveyor belt as disclosed in EU-OS No. 0,043,886. Usually, tennis balls are moved from the end of the collection trough to the container through a flexible hose by a suction system that is disposed in the ball thrower. The further movement of the balls could also be by a vertical delivery system with a circulating conveyor belt, as is disclosed in DE-OS No. 23 34 849.
The covering on the vertical rebound wall or the ramps connected thereto, respectively, has been found to be critical for the proper functioning of the systems, or as a reason for deficient functioning. In order to achieve the desired mix of elasticity and damping, which leads to the ball falling into the collection trough with the minimum of residual energy and subsequently remaining therein, DE-OS No. 23 34 089 proposes the use of "elastic damping" material, and then stretching the material. There are no further details as to which materials display these characteristics. In this regard, the proposals advanced by U.S. Pat. No. 2,280,376 appear more realistic. This provides a series of oblique nets arranged in front of the rebound wall that is in the form of a net, these oblique nets preventing the ball played against the wall from rebounding. However, implementation of these proposals is costly and the durability of the nets is dubious.
DE-OS No. 1,428,841 discloses a covering that is secured to a frame by means of springs. This almost always returns a tennis ball to the playing area, thus simulating the return of the ball by an opponent. In contrast to this, the present invention arranges for a ball that has been played against the rebound wall to drop into the collection trough with the least possible residual energy and then remain therein, in any event after another contact with the ramp. This is solved only in part by the loosely suspended hangings according to PCT-OS No. 80/01650, which is what is desired in the context of the description contained therein. In the conventional device, the impacting balls are brought to approximately the same terminal velocity at which they rebound from a rigid rebound surface, relatively independently of their initial velocity.
However, GB-PS No. 1,223,579 attempts to intercept an impacting tennis ball so that it is not returned to the playing area. To this end, a capture net is secured to pivoting side arms that permit the whole net to swing away when struck by a ball. Such a structure is not only costly from the point of view of design and space requirements, but is also confined to vertical rebound walls.